Tornadoes · United States · Missouri · 2013
EF1 tornado, Iantha to Irwin, Missouri, May 20, 2013
From Iantha to Irwin, this EF1 tornado ran 6.8 miles across Barton County on May 20, 2013, touching down at 6:03 PM CDT and reaching 100 yards wide. It killed nobody, and did $50,000 of property damage.
The rating scale
Tracks are drawn in the color of the rating. The Enhanced Fujita scale rates the damage rather than measuring the wind: the speeds are what that damage is taken to imply.
EF065 to 85 mph
Light damage. Surface peeled off some roofs, gutters and siding damaged, branches broken, shallow-rooted trees pushed over.
EF186 to 110 mphthis tornado
Moderate damage. Roofs badly stripped, mobile homes overturned or badly damaged, exterior doors lost, windows broken.
EF2111 to 135 mph
Considerable damage. Roofs torn off well-built houses, frame homes shifted on their foundations, mobile homes destroyed, large trees snapped or uprooted, cars lifted off the ground.
EF3136 to 165 mph
Severe damage. Whole stories of well-built houses destroyed, large buildings badly damaged, trains overturned, trees debarked, heavy cars lifted and thrown.
EF4166 to 200 mph
Devastating damage. Well-built houses leveled, structures with weak foundations moved some distance, cars thrown and large missiles generated.
EF5over 200 mph
Incredible damage. Strong frame houses swept off their foundations, car-sized missiles thrown more than 100 meters, steel-reinforced concrete badly damaged, high-rise buildings deformed.
Unrated
The survey recorded a tornado but could not put a number on it, most often because it crossed open country and damaged nothing a rating can be read from.
The record
- Rating
- EF1
- Date
- May 20, 2013
- Touchdown
- 6:03 PM CDT (23:03 UTC)
- Lifted
- 6:05 PM CDT (23:05 UTC)
- On the ground
- 2 minutes
- Path length
- 6.8 miles (11.0 km)
- Path width
- 100 yards (91 m)
- Deaths
- 0
- Injuries
- 0
- Property damage
- $50,000
- County
- Barton County
- Touchdown point
- 37.520, -94.424
- Lift-off point
- 37.591, -94.338
- Record number
- 1305201703-01
What the Weather Service recorded
A strong negatively titled upper level trough developed over the central portions of the country. A slow moving cold front moved into the Missouri Ozarks. This setup caused for several rounds of severe and slow moving thunderstorms which lead to widespread wind damage, large hail, and several low end tornadoes along with isolated flooding due to heavy rainfall.
An EF-1 tornado touched down 7 miles west-northwest of Lamar and tracked 7 miles to the northeast. Several trees along with a couple of outbuildings were destroyed. Winds were estimated around 95 mph.
From NOAA NCEI's Storm Events Database, the narrative the local forecast office wrote for Storm Data.
The warnings
21 minutes of warning. NWS SGF issued a tornado warning for this county at 22:42 UTC, 21 minutes before the tornado touched down, in force until 23:15 UTC.
The county was under a tornado watch, issued at 17:49 UTC and running to 01:37 UTC.
| Issued (UTC) | Expired | Product | Office |
|---|---|---|---|
| 05:13 UTC | 05:24 UTC | Tornado Warning | SGF |
| 09:46 UTC | 16:00 UTC | Flood Advisory | SGF |
| 17:49 UTC | 01:37 UTC | Tornado Watch | SGF |
| 22:42 UTC | 23:15 UTC | Tornado Warning | SGF |
| 23:14 UTC | 23:39 UTC | Tornado Warning | SGF |
| 01:00 UTC | 04:09 UTC | Flash Flood Watch | SGF |
Every warning and watch covering the touchdown point that day, from the Iowa Environmental Mesonet's archive of National Weather Service products. Lead time is measured from the issue of the warning in force to the touchdown time in the database, both of which were recorded to the minute by different people.
The forecast that day
The Storm Prediction Center had this point in a Slight Risk, with a 0.10 chance of a tornado within 25 miles. The outlook in force was issued at 19:58 UTC.
SPC's Day 1 convective outlook as it stood when the tornado began, read at the touchdown point. The same archive is on the radar archive.
The air that afternoon
The radiosonde launches on either side of the tornado, from the nearest station that was launching then, drawn and analyzed the way Storm Lab does: the same diagram, the same parcel and shear definitions SPC's mesoanalysis uses.
Springfield, MO (KSGF), 12:00Z
11.1 hours before the tornado, 89 km from the path. May 20, 2013.
- Mixed-layer CAPE
- 4 J/kg
- Mixed-layer CIN
- -445 J/kg
- Surface CAPE
- 0 J/kg
- Mixed-layer LCL
- 1092 m above ground
- 0-6 km bulk shear
- 69 kt
- 0-1 km bulk shear
- 17 kt
- 0-1 km storm-relative helicity
- 81 m²/s²
- 0-3 km storm-relative helicity
- 208 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 4.4
- 0-3 km lapse rate
- 3.5 K/km
Springfield, MO (KSGF), 00:00Z
0.9 hours after it, 89 km from the path. May 21, 2013.
- Mixed-layer CAPE
- 2135 J/kg
- Mixed-layer CIN
- -10 J/kg
- Surface CAPE
- 2535 J/kg
- Mixed-layer LCL
- 780 m above ground
- 0-6 km bulk shear
- 49 kt
- 0-1 km bulk shear
- 31 kt
- 0-1 km storm-relative helicity
- 236 m²/s²
- 0-3 km storm-relative helicity
- 265 m²/s²
- Significant tornado parameter
- 3.2
- Supercell composite
- 13.9
- 0-3 km lapse rate
- 5.7 K/km
The radar
The Springfield radar (KSGF), 94 km away, was scanning. The volume nearest the touchdown began at 23:01 UTC.
Open the radar archive at this moment, over the track
Reflectivity and velocity, decoded from the Level II archive in the browser. Volumes take a few seconds to open the first time.
What was reported nearby
Local storm reports within 60 km of the path, in the three hours either side.
| Time (UTC) | Report | Where | County | Remark |
|---|---|---|---|---|
| 22:37 UTC | TORNADO | 3 S Stockton | Cedar, MO | AN EF-0 TORNADO TOUCHED DOWN ABOUT 3 MILES SOUTH OF STOCKTON ALONG EAST 1674 ROAD. THIS TORNADO CONTINUED ON A 2.1 MILE LONG PATH THROUGH ORLEANS TRAIL PUBLIC USE AREA BEFORE LIFTING OVER STOCKTON LAKE. THERE WAS DAMAGE |
| 23:03 UTC | TORNADO | 7 Wnw Lamar | Barton, MO | AN EF-1 TORNADO TOUCHED DOWN 7 MILES WEST NORTHWEST OF LAMAR...AND TRACKED 6.78 MILES TO THE NORTHEAST. TREES ALONG WITH A COUPLE OF OUTBUILDINGS WERE DESTROYED. ESTIMATED WIDTH WAS MEASURED AT 100 YARDS AND MAXIMUM WIND |
| 23:15 UTC | TSTM WND DMG | 3 Ne Lamar | Barton, MO | ROOF DAMAGE TO BUILDING AT INTERSECTION OF HIGHWAY C AND F APPROXIMATELY 3 MILES NORTHEAST OF LAMAR. |
| 23:15 UTC | TSTM WND DMG | Lamar | Barton, MO | BUILDING DAMAGE. SEVERAL ROOFS IN LAMAR BY ESTIMATED 75 MPH. |
| 23:34 UTC | TSTM WND DMG | 2 Nnw Wagoner | Cedar, MO | BARN BLOWN INTO TRAILER HOME AND DAMAGED TRAILER. |
| 23:37 UTC | TORNADO | 3 S Stockton | Cedar, MO | AN EF-0 TORNADO TOUCHED DOWN ABOUT 3 MILES SOUTH OF STOCKTON ALONG EAST 1674 ROAD. THIS TORNADO CONTINUED ON A 2.1 MILE LONG PATH THROUGH ORLEANS TRAIL PUBLIC USE AREA BEFORE LIFTING OVER STOCKTON LAKE. THERE WAS DAMAGE |
| 23:43 UTC | TSTM WND DMG | 5 Nnw Stockton | Cedar, MO | ROOF DAMAGE TO TRAILER HOME. |
| 23:43 UTC | TSTM WND DMG | Stockton | Cedar, MO | TREES AND POWER LINES REPORTED DOWN THROUGHOUT THE COUNTY. |
From the Iowa Environmental Mesonet's archive of National Weather Service local storm reports.
This ground now
The live radar over the trackEvery 2013 tornado in MissouriEvery tornado in Missouri since 1950Warnings in force in Missouri nowThe forecast where you are
The other tornadoes of May 20, 2013
35 more were confirmed in the United States that day.
| Date | Time | Rating | Where | Path (mi) | Width (yd) | Deaths | Injuries | Damage |
|---|---|---|---|---|---|---|---|---|
| May 20 | 2:56 PM CDT | EF5 | Moore tornado, OK | 13.8 | 1,900 | 24 | 212 | $2.0 billion |
| May 20 | 2:58 PM CDT | EF0 | Stephens, OK | 1.0 | 30 | |||
| May 20 | 3:07 PM CDT | EF1 | Stephens, OK | 4.0 | 200 | $20,000 | ||
| May 20 | 3:51 PM CDT | EF1 | Washington, OK | 6.5 | 500 | $5,000 | ||
| May 20 | 4:12 PM CDT | EF0 | Montgomery, KS | 0.5 | 50 | |||
| May 20 | 4:21 PM CDT | EF1 | Washington, OK | 4.5 | 400 | $10,000 | ||
| May 20 | 4:33 PM CDT | EF1 | Washington, OK | 6.0 | 500 | $30,000 | ||
| May 20 | 4:35 PM CDT | EF0 | Brown, TX | 1.2 | 50 | |||
| May 20 | 4:40 PM CDT | EF0 | Lincoln, OK | 1.2 | 100 | |||
| May 20 | 4:50 PM CDT | EF0 | Stanton, KS | 0.4 | 50 | |||
| May 20 | 4:57 PM CDT | EF1 | Pettis, MO | 14.5 | 200 | $20,000 | ||
| May 20 | 5:05 PM CDT | EF0 | Stanton, KS | 0.3 | 50 | |||
| May 20 | 5:37 PM CDT | EF0 | Cedar, MO | 3.2 | 100 | $50,000 | ||
| May 20 | 5:41 PM CDT | EF0 | Montague, TX | 0.9 | 50 | |||
| May 20 | 5:41 PM CDT | EF1 | Brown, TX | 3.6 | 350 | $100,000 | ||
| May 20 | 4:53 PM MDT | EF0 | Alamosa, CO | 0.1 | 75 | |||
| May 20 | 6:00 PM CDT | EF0 | Brown, TX | 0.2 | 50 | |||
| May 20 | 6:25 PM CDT | EF2 | Ottawa, OK | 10.0 | 800 | $1.0 million | ||
| May 20 | 6:32 PM CDT | EF1 | Adair, OK to MO | 2.0 | 150 | |||
| May 20 | 6:32 PM CDT | EF1 | Ottawa, OK to MO | 9.3 | 600 | $250,000 | ||
| May 20 | 6:35 PM CDT | EF1 | Adair, OK | 2.5 | 300 | $15,000 | ||
| May 20 | 6:40 PM CDT | EF1 | Adair, OK to AR | 8.0 | 500 | $225,000 | ||
| May 20 | 6:49 PM CDT | EF1 | Benton, AR | 2.9 | 500 | $50,000 | ||
| May 20 | 6:49 PM CDT | EF1 | Coal, OK | 5.9 | 250 | $30,000 | ||
| May 20 | 6:56 PM CDT | EF0 | St. Clair, MO | 0.5 | 200 | |||
| May 20 | 7:24 PM CDT | EF1 | Benton, AR | 0.8 | 270 | $50,000 | ||
| May 20 | 7:24 PM CDT | EF1 | Marion, MO | 1.2 | 50 | |||
| May 20 | 7:25 PM CDT | EF0 | Mills, TX | 1.1 | 100 | |||
| May 20 | 7:50 PM CDT | EF1 | Stone, MO | 1.4 | 200 | $50,000 | ||
| May 20 | 8:05 PM CDT | EF0 | Stone, MO | 0.6 | 100 | |||
| May 20 | 8:05 PM CDT | EF1 | Stone, MO | 1.4 | 100 | |||
| May 20 | 8:33 PM CDT | EF0 | LeFlore, OK | 0.7 | 260 | |||
| May 20 | 8:44 PM CDT | EF1 | LeFlore, OK | 8.5 | 500 | $5,000 | ||
| May 20 | 8:46 PM CDT | EF0 | Morgan, MO | 0.7 | 100 | $50,000 | ||
| May 20 | 10:14 PM CDT | EF2 | Macoupin, IL | 0.2 | 75 | 3 |
What this means
Ratings are the survey's, read off the damage rather than measured; the rating scale is above. Tornado counts rise through the record as reporting improved, so a year in the 1950s is not comparable with one today except for the strongest tornadoes, which were always noticed.
Sources
NOAA Storm Prediction Center tornado database, 1950-2025, the official record kept by NOAA's Storm Prediction Center.